Getting the keyword arguments actually passed to a Python method

Question

I\'m dreaming of a Python method with explicit keyword args:

def func(a=None, b=None, c=None):
    for arg, val in magic_arg_dict.items():   # Where do I get         


        

Answer 1

Perhaps raise an error if they pass any *args?

def func(*args, **kwargs):
  if args:
    raise TypeError("no positional args allowed")
  arg1 = kwargs.pop("arg1", "default")
  if kwargs:
    raise TypeError("unknown args " + str(kwargs.keys()))

It'd be simple to factor it into taking a list of varnames or a generic parsing function to use. It wouldn't be too hard to make this into a decorator (python 3.1), too:

def OnlyKwargs(func):
  allowed = func.__code__.co_varnames
  def wrap(*args, **kwargs):
    assert not args
    # or whatever logic you need wrt required args
    assert sorted(allowed) == sorted(kwargs)
    return func(**kwargs)

Note: i'm not sure how well this would work around already wrapped functions or functions that have *args or **kwargs already.